Dental flosses have long been used to clean the teeth and the gum margin, for instance, in U.S. Pat. No. 3,800,812. In the past, certain medicinal ingredients have been bonded to or incorporated in the floss, e.g., fluoride to protect the tooth enamel from acid attack. Bactericides have also been used to counter periodontal disease.
However, the use of floss to clean the teeth-a process which is generally referred to herein as "flossing"--which is a very important technique recommended by dentists to prevent tooth and gum disease--often produces bleeding from the gums.
There have been numerous attempts in the art to provide superior dental flosses. For example, U.S. Pat. No. 3,830,246 discloses a floss of unspecified composition which is impregnated with a fluoride. No wax coating is disclosed. In U.S. Pat. No. 3,897,795 floss containing fluoride (with no wax coating) is disclosed. In U.S. Pat. No. 4,215,478 floss containing fluoride (with no wax coating) is described. U.S. Pat. No. 4,033,365 discloses a floss designed to retain flavorants over a long period of time through the use of non-wax polymeric coatings containing spray-dried flavor particles. The material constituting the floss is synthetic or natural, (but polytetraflouroethylene i.e. PTFE which, in it original form was developed by E. I. DuPont de Nemours & Co., Inc. (DuPont) and sold by that company under its Trademark Teflon, is not mentioned, nor are other types of PTFE which will be described herein).
In U.S. Pat. No. 3,771,536 floss containing fluoride with non-wax coating is described.
U.S. Pat. No. 3,943,949 discloses a floss-like material comprising a bundle of natural or synthetic fibers (but not PTFE) coated with various waxes, including microcrystalline wax, containing spray-dried flavor particles.
The prior art, as exemplified by the patents discussed above, make it clear that flossing is an extremely important adjunct to proper dental hygiene. Moreover, it is known that no floss on the market has received the degree of consumer acceptance to the degree which the dental profession would like. Indeed, in U.S. Pat. No. 3,913,596, stiff paper was proposed as a substitute for floss. The insufficient consumer acceptance--despite often repeated directions by dentists to use floss--may arise from the fact that prior art flosses frequently caused gingival bleeding and are generally uncomfortable or difficult to use. Those conditions may arise primarily from the relatively high coefficient of friction (COF) of such flosses.
Thus, because prior art flosses have such high COFs, consumers must use substantial force to pull them between the teeth or so-called "contact points". Unfortunately, the user does not know when the floss will, in fact, pass between the contact points. When this suddenly occurs, the user does not have time to release the great force being applied. This appears to cause the flosses to be pulled into the gum, causing cuts which bleed, sometimes profusely.
In order to solve this problem, it has been unexpectedly discovered that floss made of porous, high strength Expanded PTFE is extremely effective to provide hygienic tooth and gum care. Moreover, excellent effect is also provided when the floss is coated with microcrystalline wax (MCW). The MCW, surprisingly, adheres to the porous, high strength PTFE which without a coating has a very low COF(below 0.08); and when coated with MCW generally has a COF intermediate between prior art floss white and uncoated PTFE (at least 0.08 to that of commercial flosses, say to about 0.15); depending on additives which may be present, the COF may be somewhat higher say to about 0.25.. It is believed that the COF characteristics of MCW coated PTFE when reduced below about 0.15 may result from partial removal of MCW by contact at the contact points, rendering PTFE thereby exposed to slide more easily between teeth. It is also noteworthy that PTFE in its original form sold as Teflon did not have sufficient tensile strength to be effective as floss. When pulled or stretched, it would readily break. Accordingly, several major benefits accrue from the present invention. First, the tensile strength of Expanded PTFE, described below, is quite satisfactory for pressures associated with flossing; second, the COF of Expanded PTFE is generally much lower than that of existing flosses and tapes even when coated with MCW, so that the floss of this invention can pass smoothly through the very narrow spaces between the teeth, etc., and clean the teeth and gums without excessive bleeding; third, the MCW is an excellent carrier for a variety of actives and agents which promote oral hygiene even in those instances where the COF is at levels comparable to the prior art as will be described.
Thus, a primary object of this invention is to provide a floss for dental and gingival cleaning made of porous, high strength PTFE (that is Expanded PTFE) coated with MCW. An additional object is to incorporate on, below or in the MCW coating an active which promotes oral hygiene and/or other dentally acceptable agent.
Moreover, another object is to provide an Expanded PTFE floss adheringly coated with MCW which incorporates one or more coagulants which inhibit gingival bleeding, particularly in a situation where the presence of particular oral hygiene promoting actives may raise the COF, to thereby spare the user of the discomfort of the presence of blood in the oral cavity.
Materials promoting oral hygiene which may h=introduced on MCW coating of the floss include anti-plaque, anti-caries, anti-bacterial and/or tartar control actives preferably--although not necessarily--in conjunction with coagulant.
A further object of this invention is to incorporate in the MCW coating of the floss other orally acceptable agents, such as coolants, flavorants, colorants, polishing and abrasive agents and the like.